Fibrosis of the liver can be caused by activated hepatic stellate cells (HSC), resulting in a plurality of types of collagen molecules and fibronectin being deposited on interstitial tissue. This can lead to hepatic cirrhosis, hepatic failure, and/or hepatocellular carcinoma. Further, chronic pancreatitis develops as a result of pancreatic fibrosis by the same mechanism as that for hepatic fibrosis (Madro, et al., 2004; Med Sci Monit. 10:RA166-70; Jaster, 2004, Mol. Cancer. 6:26). Furthermore, stellate cells are present in disorders of the vocal cord and larynx such as vocal cord scarring, vocal cord mucosal fibrosis, and laryngeal fibrosis. To prevent or treat fibrosis in these organs and elsewhere in the body, there is a desire for the development of a drug carrier and drug carrier kit.
Stellate cells are one of the important target candidates for treating fibrosis (Fallowfield et al., 2004, Expert Opin Ther Targets. 8:423-35; Pinzani, et al., 2004, Dig Liver Dis. 36:231-42). During fibrosis, stellate cells are activated by cytokines from nearby cells to produce many factors that cause hepatic fibrosis. Stellate cells store vitamin A, and belong to the myofibroblast family.
Therapeutic methods to prevent or treat fibrosis attempt to control collagen metabolism, promotion of the collagen degradation system, and inhibition of activation of stellate cells. However, in all these cases, the low specificity of action and/or the low organ specificity, limited efficacy and adverse side effects create problems.
Inhibition of collagen protein synthesis has not been established as a therapeutic method. The potency of molecules targeting collagen production is limited due to the possibility of causing side effects. Inhibiting collagen production directly provides another therapeutic method to prevent or treat fibrosis. Such a method requires controlling one or more of the various types of collagen Types I to IV. A method for accomplishing this may be through heat shock protein47 (HSP47), a collagen-specific molecular chaperone that is essential for intracellular transport and molecular maturation necessary for various types of collagen. Therefore, if the function of HSP47 can be specifically controlled in stellate cells, there is a possibility of inhibiting hepatic fibrosis.